Detection of early xerophthalmia by impression cytology
J. R. Wittpenn, S. C. Tseng and A. Sommer
Vitamin A deficiency causes blindness, increased systemic morbidity, and
increased mortality among preschool children in many developing nations.
Presently, there is no simple, reliable test to detect early,
physiologically significant vitamin A deficiency. We used conjunctival
impression cytology results to evaluate children with early xerophthalmia
before treatment and again three to eight weeks later. Subsequently, we
modified our technique. We then compared children with early xerophthalmia
to normal children. Conjunctival impressions from children with
xerophthalmia all showed complete loss of goblet cells and the appearance
of enlarged, partially keratinized epithelial cells. Conjunctival
impressions from treated and normal children showed normal goblet cells and
sheets of small epithelial cells. These results suggest impression cytology
may represent the first simple, objective, diagnostic test for the
detection of early vitamin A deficiency.
